Trenching excavators typically utilise cutting teeth mounted on a chain or belt passing along a trenching arm to cut along an advancing face of the trench. The chain runs out of the excavation along the advancing face of the trench, and returns to its starting point through the previously-excavated part of the trench. The width of the trench produced is governed by the width of the cutter assembly mounted along the chain, and the return strand is thus a neat fit within the previously-excavated part of the trench. There is thus the inevitability of contact between the return strand and the sides of the trench, with consequent parasitic power consumption, cutter wear and damage to the trench faces. These problems are exacerbated if the trenching arm must be rotated within the trench to correct the trench alignment, or to cut a curved trench.
The present invention aims to alleviate the above disadvantages and to provide trenching apparatus which will be reliable and efficient in use. Other objects and advantages of this invention will hereinafter become apparent.